I think first of all , be respectful and polite , and p thank them for a good evening , but be straight up , and honest , the longer you leave your feelings of they are not right for you the harder it is for both parties .
As to regarding your profile and a blind date , you need to be comfortable with your profile and your honestly , before posting it on the date site , it’s not about the immediate date or response, it’s about the right matchs individual you , done you would like to share time with , then you will be more connected.
Blind date are ok if you are go into the evening with no expectations and you present yourself as you , feel comfortable , if it not right just be polite and end it , respectfully